Over the next two years, the eight-mile stretch of Nine Mile Creek running through Hopkins will be transformed from a muddy drainage ditch into a pretty, meandering stream.
Starting this month and during winters when the water is low, workers for the Nine Mile Creek Watershed District will relieve the creek of overgrown brush, soften the slope of its banks, line its bed with smooth river stones, and reroute it into a curving channel through Hopkins' Valley Park.
"Right now it's a glorified drainage ditch," said Hopkins city engineer John Bradford. "It's going to be a more attractive amenity and increase the natural habitat of the creek for wildlife."
The ambitious $4.5 million Hopkins project is aimed at stopping erosion and making the water more hospitable to fish.
The project will "re-meander" the creek from a straight channel dug in the 1960s and 1970s and return it to its original location, said Bob Obermeyer of Barr Engineering, the watershed district's engineer. He said the district has no record of why it was moved and straightened.
Eric Evenson, director of Minnehaha Creek Watershed District, said many creeks were straightened years ago to accommodate development or farming or to increase drainage.
Minnehaha Creek was re-meandered near Methodist Hospital in St. Louis Park in 2008. In 2010, the Department of Natural Resources and Trout Unlimited will put curves back into the Vermillion River.
The restored segment of Nine Mile Creek will have the curving channel and gently sloping sides of a natural stream instead of steep, straight banks with sloughing dirt and exposed tree roots, said watershed district director Kevin Bigalke said. "From the public's perspective it will be a significant enhancement," he said.
Springing from humble headwaters at a drainage culvert under Excelsior Boulevard, the north branch of Nine Mile Creek is nearly invisible in many places in Hopkins. It runs through private industrial property, then more visibly flows past Valley Park on its way to a marshy wetland near Hwy. 169, where it continues east into Edina.
The renovation will install a big new bend in the creek to make it part of Valley Park, moving it from its current low profile location along one edge of the park.
Erosion prompted the project. Besides the fact that the dirty creek sends sediment into the Minnesota River and ultimately the Gulf of Mexico, the constant cutting away of dirt from the creek banks has brought it too close to some city streets and private property, Bradford said.
When Hopkins petitioned the watershed district to move the creek away from Westbrooke Way by rechanneling it into Valley Park, the district responded with the larger restoration project.
This winter the district will spend $1.6 million to restore the first 4.2 miles of the creek from Excelsior to 9th Avenue S. -- most of which is on private property and visible to the public only from the Minnesota River Bluffs Regional Trail running from Hopkins to Chanhassen.
The backhoe rechanneling through the park and wetland is planned to start in the winter of 2011 at an estimated cost of $2.9 million, Obermeyer said.
Dirt removed from the new channel will be saved to fill in the old channel when the water is rerouted, probably in spring 2012, he said. The district plans to give the grasses planted on the banks of the new channel a season to grow before the creeks flows through.
The creek is on the state's impaired waters list because its muddy flow "doesn't support the fish species that a creek of this type should," Bigalke said. Halting the erosion is expected to attract more waterfowl and fish.
Now the stream is so deep it rarely overflows its banks, Bigalke said. Instead, rushing stormwater scours the bottom, undercutting the banks and causing them to fall in. Lining the bed with river stone will stop the bottom scouring.
Slowing the water down by giving the creek curves and riffles will allow sediment to drop out and inject more oxygen into the water, Bigalke said.
The meandering channel also will provide more shade over the water, keeping the creek cooler, Obermeyer said. "The cooler the water, the better for the fish."
The Hopkins project will restore the creek to Hwy. 169 on the border with Edina. Edina has petitioned the watershed district for similar treatment of the creek within its borders. That work is not yet scheduled.
Laurie Blake • 612-673-1711